package com.itheima.reggie.filter;

import com.alibaba.fastjson.JSON;
import com.itheima.reggie.common.BaseContext;
import com.itheima.reggie.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.AntPathMatcher;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

//        过滤器别名                         拦截所有请求
@WebFilter(filterName = "loginCheckFilter", urlPatterns = "/*")
@Slf4j
public class LoginCheckFilter implements Filter {
    //路径匹配器
    public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();

    @Override
    public void doFilter(
            ServletRequest servletRequest,
            ServletResponse servletResponse,
            FilterChain filterChain
    ) throws IOException, ServletException {

        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

//        A. 获取本次请求的URI
        String requestURI = request.getRequestURI();

        log.info("拦截到请求：{}", requestURI);

        String[] urls = new String[]{
                "/employee/login",
                "/employee/logout",
                "/backend/**",
                "/common/**",
                "/front/**"
        };

        // B. 判断本次请求, 是否需要登录, 才可以访问
        boolean check = check(urls, requestURI);

        //C. 如果不需要，则直接放行
        if (check) {
            log.info("本次请求{}不需要处理", requestURI);
            filterChain.doFilter(request, response);
            return;
        }
        //D. 判断登录状态，如果已登录，则直接放行
        if (request.getSession().getAttribute("employee") != null) {
            log.info("用户已登录，用户id为：{}",request.getSession().getAttribute("employee"));
            Long  employee = (Long) request.getSession().getAttribute("employee");
            BaseContext.setCurrentId(employee);
            filterChain.doFilter(request, response);
            return;
        }
        log.info("用户未登录");

        // E. 如果未登录, 则返回未登录结果
        response.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));
    }

    /**
     * 路径匹配， 检查本次请求是否需要放行
     *
     * @param urls
     * @param requestUrl
     * @return
     */
    public boolean check(String[] urls, String requestUrl) {
        for (String url : urls) {
            boolean match = PATH_MATCHER.match(url, requestUrl);
            if (match) {
                return true;
            }
        }
        return false;
    }
}
